TY - JOUR
T1 - Proteasome inhibitors activate the transcription factors C/EBP-β and δ in human intestinal epithelial cells
AU - Hungness, Eric S.
AU - Robb, Bruce W.
AU - Luo, Guang Ju
AU - Pritts, Timothy A.
AU - Hershko, Dan D.
AU - Hasselgren, Per Olof
PY - 2002
Y1 - 2002
N2 - In recent studies, induction of the heat shock response by hyperthermia upregulated the expression and DNA binding activity of the transcription factor C/EBP. This is an important observation because it may at least in part explain why the heat shock response upregulates IL-6 production in the intestinal mucosa and in the enterocyte. A novel method to induce the heat shock response is proteasome inhibition. The influence of this treatment on the expression and DNA binding activity of C/EBP is not known. We treated cultured Caco-2 cells, a human intestinal epithelial cell line, with one of the proteasome inhibitors, MG-132 or lactacystin, and measured C/EBP-β and δ DNA binding activity by electrophoretic mobility shift assay and supershift analysis. In addition, nuclear levels of C/EBP-β and δ protein were determined by Western blot analysis. Treatment of the cells with the proteasome inhibitors resulted in increased cellular levels of heat shock protein 72, consistent with induction of the heat shock response. Treatment also resulted in increased DNA binding activity and nuclear protein levels of C/EBP-β and δ. The effects of the proteasome inhibitors on C/EBP were inhibited by treating the cells with quercetin, a substance known to block the heat shock response. The results suggest that proteasome inhibition activates the transcription factors C/EBP-β and δ in human intestinal epithelial cells and that this response, at least in part, is caused by induction of the heat shock response. The observations are important because they provide support for a novel method to influence gene activation in the enterocyte.
AB - In recent studies, induction of the heat shock response by hyperthermia upregulated the expression and DNA binding activity of the transcription factor C/EBP. This is an important observation because it may at least in part explain why the heat shock response upregulates IL-6 production in the intestinal mucosa and in the enterocyte. A novel method to induce the heat shock response is proteasome inhibition. The influence of this treatment on the expression and DNA binding activity of C/EBP is not known. We treated cultured Caco-2 cells, a human intestinal epithelial cell line, with one of the proteasome inhibitors, MG-132 or lactacystin, and measured C/EBP-β and δ DNA binding activity by electrophoretic mobility shift assay and supershift analysis. In addition, nuclear levels of C/EBP-β and δ protein were determined by Western blot analysis. Treatment of the cells with the proteasome inhibitors resulted in increased cellular levels of heat shock protein 72, consistent with induction of the heat shock response. Treatment also resulted in increased DNA binding activity and nuclear protein levels of C/EBP-β and δ. The effects of the proteasome inhibitors on C/EBP were inhibited by treating the cells with quercetin, a substance known to block the heat shock response. The results suggest that proteasome inhibition activates the transcription factors C/EBP-β and δ in human intestinal epithelial cells and that this response, at least in part, is caused by induction of the heat shock response. The observations are important because they provide support for a novel method to influence gene activation in the enterocyte.
UR - http://www.scopus.com/inward/record.url?scp=0036298130&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0036298130&partnerID=8YFLogxK
U2 - 10.1006/bbrc.2001.6168
DO - 10.1006/bbrc.2001.6168
M3 - Article
C2 - 11779194
AN - SCOPUS:0036298130
VL - 290
SP - 469
EP - 474
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
IS - 1
M1 - 96168
ER -